--- In morelife@yahoogroups.com, Ólafur Páll Ólafsson <olafurpall@...>
wrote:
[snip]
> > Perhaps there is a role for sublingual or bucchal P5P? It sounds like
> > not much might be needed.
>
> Yes this is a case where such administration might prove to be
> beneficial. However I searched for and did not find any studies on
> sublingual or buccal administration of PLP. I wouldn't count on much
> of it being absorbed by such a route. I suggest waiting for further
> research until it is determined exactly how effectively PLP is
> absorbed by a sublingual or buccal route.
[snip]

I haven't tried it personally and don't know how effectively it is
absorbed, but Source Naturals makes a 25 mg coenzymated sublingual PLP
product.

Stephen

META:I am commenting on this immediately because I think that there
may be a chance for people to be led astray if I don't./META

[First please read the definitions, of catalyst, enzyme, cofactor and
coenzyme at: http://morelife.org/glossary/index.html

Kitty spent many, many hours on this Glossary which few people seem to
ever use. The latter is the major reason why it was never completed.

All forms of B6 must be dephosphorylated (hydrolyzed by a phosphatase
enzyme) in order to be absorbed. This is because they are absorbed by
first being taken into the intestinal border cells and all molecules
of this kind must be in their non-phosphorylated form to pass through
a cell membrane. When released from any cell into serum, all B6
molecules (similar to many other B molecules) are re-phosphorylated
(by the action of a kinase enzyme). For intestinal absorption this
happens when a B6 molecule is released from an intestinal cell into
the capillary serum which is then transported via the portal vein to
the liver. While all of the B6 in the serum is in the phosphorylated
form, once inside cells the two forms both exist in equilibrium with
the phosphorylated form being the only one that can aid useful human
biochemical reactions (except for anti-glycation purposes, PLP aids
far more reactions than does PMP, and PNP aids none at all).

The result of all this for my immediate purposes is to question what
is the meaning of the phrase "coenzymated PLP" used by Source natural
(since PLP is already a coenzyme form). In my experience, I have found
supplement suppliers to be guilty of using the "technical terms" of
nutrition and biochemical sciences (most of which they do not
understand) in order to *impress* their potential customers and
increase sales of their products.

Furthermore, I seriously question the entire notion that sublingual
use of PLP will be any better than normal ingestion (and it will still
need to be absorbed *through* the cells of the mouth, being
dephosphorylated as it is taken into those cells and rephosphorylated
again as it is released into the capillaries).

The standard reason for sublingual use of supplements is *to prevent
immediate transformation to something less useful by the liver* to
which everything absorbed intestinally first goes. However, immediate
passage to the liver *does not negatively affect* any form of B6.
Rather, it is the main method of conversion of pyridoxine in order to
make it useful.

For the above reasons, although there is certainly nothing unhealthful
about taking these phosphated forms (which are somewhat more stable
that the unphosphated forms), based on the biochemical and
physiological mechanisms of use as I understand them, I see no reason
for spending any extra money on these forms and particularly not the
generally even more expensive sublingual forms.

As an afterthought, since the liver also transforms some PM to PL,
which makes the digestively taken PM of less anti-glycation value (in
my reading of many advanced texts and scientific papers), in theory it
might be advantageous to take pyridoxamine sublingually. --Paul]